This invention relates to agricultural combines and more particularly to an improved system for compensating for the downhill drift of crop material in the combine when the combine is operating on side hills.
The grain separating mechanism of a conventional combine, as opposed to an axial flow-type combine, includes an axially transverse threshing cylinder and concave and a bank of straw walkers behind the threshing cylinder. Grain and other crop material, such as chaff, passing through the concave and the straw walkers falls onto a generally horizontal conveyor for delivering the crop material to a grain cleaning mechanism, which separates the clean grain from the chaff and other crop material.
A long standing problem for this type of machine has been the tendency of crop material to migrate to the downhill side of the combine when the combine is being operated on uneven terrain, the steeper the lateral slope of the combine, the greater the problem. The buildup of crop material on the downhill side of the machine either requires the operator to slow down the machine to reduce the overall flow rate of crop material through the machine, so that the downhill side of the grain separating mechanism is not overloaded, or alternately to accept higher grain losses that result from an overload of one side of the grain cleaning and separatin mechanisms within the machine.
One solution to the problem has been to provide for vertical adjustment of the combine wheels, so that the combein body and the separating mechanisms therein are maintained in a generally level condition. Another solution has been to provide for self-leveling of just the cleaning shoe portion of the separator, so that the crop material does not overload the downhill side of at least the cleaning mechanism. However, both of these solutions are relatively expensive and complicated.
A more economical and practical partial solution to the problem has been to provide generally upright, fore-and-aft vanes in the material conveying systems, including the conveyor that delivers crop material to the cleaning shoe, or some other means of channelizing the flow of crop material, so that it does not all collect on the downhill side of the machine. It is also known to provide for lateral adjustment of such vanes, so that the crop material is directed toward the uphill side of the machine to compensate for the gravity influenced downhill drift of crop material. Such a system is shown in U.S. Pat. No. 2,189,706, which discloses angularly adjustable vanes, with a pendulum-type control mechanism for automatically adjusting the angle of the vanes according to the degree of lateral inclination of the combine operating on a side hill.